Thread-chain cutter for sewing machines



Nov. 16, 1943. H, HACKLANDER 2,334,672 r THREAD-CHAIN CUTTER FOR SEWING MACHINES Filed sept. 16, 1941 Patented Nov. 16,

y Hans Hacklander, Linden, N. J., assigner to The Singer llanufacturin N. J., a corporation of New Jersey.

Company.- Elisabeth,

Application September 16, 1941, Serial No. 410,987

4 Claims. (Cl. 112252) This -invention relates to Aimprovements in thread-chain cutters for sewing machines of the typel wherein the materialv stitched is adapted to beV supported andv fedthrough the machineA by feeding wheels or "cups. Machines ofthis type are customarily employed for seaming hQsiery and the like.

In the seaming of hosiery the sewing machine used for effecting the seam-closing operation is required to be tted with a thread-chain cutter at the discharge side of the usual feed-cups. In prior machines the custom has been to provide a thread-chain cutter of the type comprising a horizontal plate-member secured at one end to the machine-frame and at its free end provided with a thread-notch sharpened along one side to provide a cutting edge.- Such a thread-chain cutter is illustrated in the U. S. patent to J. R.

Moffatt, No. 1,150,614, issued Aug. 17, 1915. It will be understood that in a thread-chain cutter of the type shown in the Moiatt patent the platemember at its free end must not extend across the normal line of seam-formation, otherwise the end of the plate-'member would interfere with the feeding of the work through the machine, as well as render it more diiilcult to properly introduce the work between the feed-cups. Since the free end of the plate-member terminates on the inner feed-cup side of the normal line of seamformation, the thread-chain cutting notch also is disposed to one side of the normal line of seam-formation. This out-of-line position of the thread-chain cutter results in disadvantages. One of these disadvantages is that the threadchain cutting notch is of necessity disposed at too great a distance from the point at which the complemental stitch-forming implements cooperate. This results in the formation of a rather long thread-chain which must be cut of! in a subsequent hand operation after the stocking is seamed. Another of these disadvantages is that, since the thread-chain cutting notch is positioned on the inner feed-cup side of the normal line of seam-formation, the thread-chain extending from the usual stitch-iinger into the threadchain cutting notch is at an angular relation relative to the normal line of seam-formation. Tension applied to the thread-chain in the severing operation reacts along the thread-chain and tends to bend the delicate free end of the stitchlinger out of its normal position. When the cutting edge of the cutter becomes dull and a stronger pull must be exerted upon the threadchain to eilect cutting thereof the stitch-finger is frequently broken. Repeated replacements of new for broken stitch-fingers is an expensive practice, inasmuch as each stitch-linger must be carefully machined and highly polished and is therefore expensive to purchase.

Therefore, it is the primary object of the present invention to provide an improved threadchain cutter designed so that it may be positioned close to the point at which thethread-handling implements cooperate in they vformation of stitches.

It is another object of the invention to provide a simple thread-chain cutter which can be successfully operated without permanently bending or breaking the delicate stitch-finger.

'I'he foregoing and other objects and advantages, together with means whereby the same may be carried into effect, will best be understood from the following description of a preferred em- 1 bodiment thereof illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary horizontal sectional view of a cup-feed sewing machine, such as disclosed in my copending patent application Serial No. 296,031, filed Sept. 22, 1939,V embodying the improvement.

Fig. 2 is an enlarged fragmentary perspective view of the elements of the machiney at and adjacent to the stitching point, showing clearly the relation between the stitch-iinger and the thread-chain cutting notch.

Fig, 3 is an enlarged top plan view of the feedcups,` stitch-forming devices, stitch-nger and novel thread-chain cutter, illustrating the manner in which the stitches are formed in the material and about the stitch-linger.

Fig. 4 is a view substantially the same as Fig. 3, showing the thread-chain which is formed at the end of the hosiery seaming operation posi-- tioned in the cutting notch.

Fig. 5 is a perspective View of the presserspring showing the thread-chain cutting notch formed in the supporting lip thereof.

Referring in detail to the drawing, the machine in which one embodiment of the invention is incorporated includes a machine-frame having a standard I which supports an inner feed-cup 2 cooperating with an outer feed-cup 3 depending from the machine-frame. The two feed-cups 2 and 3 are positively driven in synchronism and are adapted to support and feed the material being sewn past the stitch-forming devices.

The stitch-forming devices of the machine i1- lustrated comprise a threaded needle 4 carried by an endwise reciprocatory needle-bar 5, an oscil- 4latory threaded looper 6, and an oscillatory spreader 1 attached to one end of a spreader rock-shaft 8. As clearly shown and described in my above mentioned copending application Serial No.'296,031, the needle-bar 5, the looper 6 and the spreader rock-shaft 8 are operatively connected within the machine-frame to an actuating shaft, and are properly timed and actuated to effect the formation of a two-thread overseam.

As is common in cup-feed machines'of the type disclosed, there is provided a stitch-finger (see Figs. 2, 3 and 4) overlying the feed-cups 2 and 3 at the stitching point and about which the stitches are formed and set to minimize distor- 'tion of the marginal edges of the material being sewn. The `stitch-finger in the accompanying drawings comprises an attenuated 'substantially conical blade 8 terminating in a shank III secured by two screws II upon a support I2 disposed within the upturned peripheral flange 2' of the inner feed-cup 2 and sustained byv two screws I3 to an angle-bracket I4 fastened by screws I5 to the wall of the standard I.

In the operation of the machine, the threaded needle 4, after penetrating the marginal edges o'f the material, shown as M in Fig. 3, is withdrawn and during the initial portion of its withdrawal stroke casts out a needle-thread-loop TN (Fig. 2) which is entered by the point of the threaded looper 6. The looper, after entering the needle-thread-loop, carries its own thread Tr. over the marginal edges of the material N and presents said thread Tr. to the spreader 1 which distends the looper-thread-loop for entrance by the needle 4 prior to its next penetration of the fabric. The looper 6 in carrying its thread Tr. over the marginal edges of the material M lays the looper-thread over the blade 9 of the stitch-finger and the spreader 'I' distends the limb of the looper-thread thus carried over the blade 9 downwardly to a position where the advancing needle 4 enters the louper-threadloop and then passes through the material N beneath the blade 9 of the stitch-nger. In this manner the stitches are formed about the stitchfinger. In the absence of any material M between the two feed-cups 2 and 3, the stitch-finger serves as a support about which the stitches are formed, thus facilitating the formation of the usual thread-chain. The stitches formed in the material M are set when they are about the blade 9 of the stitch-finger and if the setting action is suiiicient to tightly set the stitches they tend to cling slightly to the blade 9 of the stitchi'lnger. The consequent resistance to the free passage of the material through the machine results in a puckering of the material unless additional means is" provided to augment the .feeding action of the usual cooperating feed-cups 2 and 3.

To this end, the machine illustrated is fitted with a presser-spring I6 having a work-engaging section I1 adapted to yieldingly press the material into contact with the serrated face of the outer feed-cup 3 rearwardly of the stitching point. The presser-spring cooperates with the driven feed-cup 3 to effect a pull-feed action on the material, which action assists the feedcups in advancing the material through the machine at a uniform rate. For a more complete disclosure of the presser-spring reference may be had to my copending application Serial No. 368,793, filed Dec. 6, 1940. 'Ihe free end of the presser-spring I6 is formed with a flat supporting lip I8 bent into a substantially horizontal 75 position to rest upon the upper edge of the peripheral flange 2 of the inner feed-cup 2, thereby to provide means for maintaining'the workengaging section I1 of the presser-spring in proper elevated position for cooperation with the outer feed-cup 8. Formed in the flat supporting lip I8 and preferably opening into the rear edge thereof is` a V-shaped notch I9, the sides of which are sharpened to provide cutting edges against which the thread-chain may be drawn and cut. As clearly shown in Fig. 4, the V-shaped thread-chain cutting notch I9 is disposed in the supporting lip I8 so that when the thread-chain, shown as To in Fig. 4, is positioned in the notch for severance the same extends from the stitch-nger to the notch in a line passing through the longitudinal axis of the blade 9 of the stitch-finger. When the thread-chain Tc is in this in-line position with the blade 9 a pull applied to the thread-chain to eifect the cutting thereof does not bend the delicate blade 9 of the stitch-finger out of its normal position. Even after the cutting edges of the notch I9 become slightly dull an increased pull on the threadchain necessarily applied to effect the severing thereof does not in any Way affect the stitchnger. l

Another important advantage of the present invention is the close proximity of the threadchain cutting notch to the stitching point. It has long been the endeavor of the trade to provide hosiery seaming machines with a thread-chain cutter disposed adjacent the stitching point so that the thread-chain may be severed close to the beginning and ending of the seam. It will be obvious from Fig. 4 that by forming the Cutting notch I9 in the supporting lip I8 of the presser-spring a thread-chain cutter is provided which is positioned as close to the stitching point as is practical.

In order to facilitate the manual introduction of the thread-chain into the cutting notch I9 one of the sides of the notch is extended, as at 20, beyond the end of the other side of the notch, and the rear edge ZI of the supporting lip I8 is cut at an angle to lead the, thread-chain into the cutting notch I9. It will be understood that in introducing the thread-chain into the cutting notch I9, the machine-operator need only lay the thread-chain over the supporting lip I8 and pull the same in a direction downwardly and toward the outer feed-cup 3. In the event the threadchain does not enter the cutting notch I9 directly but contacts the rear edge 2I of the lip I8, the thread-chain readily slides along the rear edge 2l and into the cutting notch I9. When the thread-chain is positioned in the cutting notch I9 a slight pull on the thread-chain will sever the same. When the sharpened edges of the cutting notch become dull the entire presser-spring I6 can be taken off the machine by removing one of the securing screws I5 and the edges of the cutting notch resharpened on a. suitablegrinding wheel or stone.

While I have shown the preferred embodiment of the present invention, it is to be understood that other embodiments of the device may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus set forth the nature of the invention what I claim herein is:

1. A sewing machine having, in combination, stitch-forming devices, a stitch-finger having an attenuated blade, a pair of circularly moving feed-cups provided with cooperating work-engaging faces for supporting and feeding material past said stitch-forming devices, a member located on the discharge side oi.' the feed-cups for engaging the material and urging it into contact with the work-engaging face of one of said feedcups and having a thread-chain cutting notch therein arranged so that its eiective cutting portion is located in substantial alinement with the axis of said stitch-finger blade, said thread-chain cutting notch having one of its sides projecting beyond the end of the other side to provide means facilitating the introduction of the. thread-chain into the cutting notch.

2. A sewing machine having, in combination, stitch-forming devices, a stitch-iinger having an attenuated blade, a pair of circularly moving feed-cups provided with cooperating work-engaging faces for supporting and feeding material past said stitch-'forming devices, a presser-member operable at the discharge side of the feedcups for assisting the feed-cups in advancing the material, and thread-chain cutting means provided on said presser-member` in close proximity to the stitch-forming devices and having an effective cutting portion disposed in substantial alinement with the axis of said stitch-iinger blade.

3. A combination presser-member and threadchain cutter for use on sewing machines having cooperating feed-cups for supporting and advanclng the material through the machine, comprising, a body portion, a work-engaging section adapted to press the material into contact with the periphery of one of said feed-cups, and a supporting lip adapted to rest upon the periphery of one of said feed-cups and having formed therein a thread-chain cutting notch provided with a mouth opening into one of the edges of said lip.

4. A sheet-metal combination presser-member material into contact with the work-engaging face of one of said feed-cups, and a supporting lip extending from said body portion adjacent said work-engaging section and adapted to rest upon the periphery ofone of said feed-cups, said supporting lip having formed therein a thread-chain cutting notch provided with a mouth opening into one of the edges of said lip.

` HANS HACKLANDER. 

